Organic luminescence display device and method of manufacturing the same

ABSTRACT

An organic luminescence display device includes a substrate, a display unit on the substrate, a thin-film encapsulation layer sealing the display unit, and a stress-reducing layer on the thin-film encapsulation layer, wherein the stress-reducing layer includes an organic molecular film.

RELATED APPLICATION

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 CFR 1.57. Thisapplication claims the benefit of Korean Patent Application No.10-2015-0087585, filed on Jun. 19, 2015, in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein in itsentirety by reference.

BACKGROUND

Field

The disclosure relates to an organic luminescence display device and amethod of manufacturing the same.

Description of the Related Technology

An organic luminescence display device includes a hole injectionelectrode, an electron injection electrode, and an organiclight-emitting device including an organic emission layer between thehole injection electrode and the electron injection electrode, and is aself-emission display device that emits light in such a way that in theorganic emission layer, holes provided by the hole injection electroderecombine with electrons provided by the electron injection electrode togenerate excitons, which change from an exited state to a ground state,generating light.

Organic luminescence display devices, which are self-emission displaydevices, do not require a separate light source. Hence, they can bedriven at a low voltage, are lightweight and thin, and have wide viewingangles, high contrast, and short response speeds. Due to thesehigh-quality characteristics, organic luminescence display devices aregaining more importance as future-generation display devices.

SUMMARY

One or more exemplary embodiments include an organic luminescencedisplay device and a method of manufacturing the same.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the presented exemplary embodiments.

According to some embodiments, an organic luminescence display deviceincludes: a substrate; a display unit on the substrate; a thin-filmencapsulation layer sealing the display unit; and a stress-reducinglayer on the thin-film encapsulation layer, wherein the stress-reducinglayer includes an organic molecular film.

In some embodiments, the stress-reducing layer may have a thickness ofabout 1 nm to about 3 nm.

In some embodiments, the stress-reducing layer may include aself-assembled monolayer.

In some embodiments, the self-assembled monolayer may include an alkylchain being a body part thereof, a reactive group linked to the alkylchain and attached on the thin-film encapsulation layer, and afunctional group linked to the alkyl chain, the reactive group isselected from silane, a carboxylic acid, and a phosphonic acid, and thefunctional group is selected from NH₂, OH, COOH, and an alkyl group.

In some embodiments, the stress-reducing layer may include a fatty acid.

In some embodiments, the fatty acid may be a stearic acid having acarbon chain.

According to one or more exemplary embodiments, a method ofmanufacturing an organic luminescence display device includes: preparinga carrier substrate; forming a display unit on the carrier substrate;forming a thin-film encapsulation layer sealing the display unit;forming a stress-reducing layer on the thin-film encapsulation layer;and forming a top protection film on the stress-reducing layer, whereinthe stress-reducing layer includes an organic molecular film.

In some embodiments, the stress-reducing layer may have a thickness ofabout 1 nm to about 3 nm.

In some embodiments, the stress-reducing layer may include aself-assembled monolayer.

In some embodiments, the stress-reducing layer may include a fatty acid.

In some embodiments, the fatty acid may include a stearic acid having acarbon chain.

In some embodiments, the method may further include, after preparing thecarrier substrate, forming a sacrificial layer on the carrier substrate.

In some embodiments, the sacrificial layer may include an inorganicmaterial and has a thickness of about 500 nm to about 2000 nm.

In some embodiments, the sacrificial layer may include molybdenum oxide.

In some embodiments, the method may further include, after the formingthe top protection film, removing the carrier substrate by irradiatingwith a laser, the sacrificial layer to separate the carrier substratefrom the display unit.

In some embodiments, the stress-reducing layer may include aself-assembled monolayer, and when irradiated with a laser, thestress-reducing layer expands, and after the carrier substrate isremoved, the stress-reducing layer shrinks.

In some embodiments, the stress-reducing layer may include a fatty acid,and when irradiated with a laser and after the carrier substrate isremoved, the stress-reducing layer changes in phase.

In some embodiments, when irradiated with a laser, the stress-reducinglayer may be liquefied, and after the carrier substrate is removed, thestress-reducing layer may be re-solidified.

In some embodiments, the method may further include, after the carriersubstrate is removed, attaching a substrate on the display unit; andremoving the top protection film.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects will become apparent and more readilyunderstood from the following description of the exemplary embodiments,taken in conjunction with the accompanying drawings in which:

FIG. 1 is a schematic cross-sectional view of an organic luminescencedisplay device according to an exemplary embodiment;

FIG. 2 is a schematic enlarged view of a display unit illustrated inFIG. 1;

FIG. 3 is a cross-sectional view of an organic luminescence displaydevice according to an exemplary embodiment, including an enlarged viewof a thin-film encapsulation layer constituting the organic luminescencedisplay device;

FIG. 4A is a cross-sectional view of a stress-reducing layer including aself-assembled monolayer (SAM), constituting an organic luminescencedisplay device according to an exemplary embodiment;

FIG. 4B is a cross-sectional view of a stress-reducing layer includingfatty acid, constituting an organic luminescence display deviceaccording to an exemplary embodiment;

FIGS. 5A-5D illustrates molecular structures of embodiments of the SAM;

FIG. 5E illustrates a molecular structure of a stearic acid, which is anexample of a fatty acid;

FIGS. 6A to 6E illustrate cross-sectional views of an organicluminescence display device to explain a method of manufacturing theorganic luminescence display device according to an exemplaryembodiment; and

FIGS. 7A to 7E illustrate cross-sectional views of an organicluminescence display device to explain a method of manufacturing anorganic luminescence display device according to another exemplaryembodiment.

DETAILED DESCRIPTION

Reference will now be made in detail to exemplary embodiments, examplesof which are illustrated in the accompanying drawings, wherein likereference numerals refer to like elements throughout. In this regard,the present exemplary embodiments may have different forms and shouldnot be construed as being limited to the descriptions set forth herein.Accordingly, the exemplary embodiments are merely described below, byreferring to the figures, to explain aspects of the present description.As used herein, the term “and/or” includes any and all combinations ofone or more of the associated listed items. Expressions such as “atleast one of,” when preceding a list of elements, modify the entire listof elements and do not modify the individual elements of the list.

The present disclosure will now be described more fully with referenceto exemplary embodiments. The disclosure may, however, be embodied inmany different forms and should not be construed as being limited to theembodiments set forth herein; rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the concept of the disclosure to those skilled in the art.Advantages, features, and how to achieve them of the present disclosurewill become apparent by reference to the embodiment that will bedescribed later in detail, together with the accompanying drawings. Thisdisclosure may, however, be embodied in many different forms and shouldnot be limited to the exemplary embodiments.

Hereinafter, embodiments are described in detail by referring to theattached drawings, and in the drawings, like reference numerals denotelike elements, and a redundant explanation thereof will not be providedherein.

As used herein, the terms as “first”, “second”, etc., are used only todistinguish one component from another, and such components should notbe limited by these terms.

As used herein, the singular forms “a,” “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise.

It will be further understood that the terms “comprises” and/or“comprising” used herein specify the presence of stated features orcomponents, but do not preclude the presence or addition of one or moreother features or components.

It will be understood that when a layer, region, or component isreferred to as being “on” or “onto” another layer, region, or component,it may be directly or indirectly formed on the other layer, region, orcomponent. That is, for example, intervening layers, regions, orcomponents may be present.

Sizes of components in the drawings may be exaggerated for convenienceof explanation. In other words, since sizes and thicknesses ofcomponents in the drawings are arbitrarily illustrated for convenienceof explanation, the following embodiments are not limited thereto.

When an embodiment is implementable in a different manner, a particularprocess sequence may be different from that already described. Forexample, although two processes are explained in a sequential manner,the processes may be performed substantially simultaneously or theprocess sequence may be the opposite to that explained already.

FIG. 1 is a schematic cross-sectional view of an organic luminescencedisplay device 1000 according to an exemplary embodiment. FIG. 2 is aschematic enlarged view of a display unit illustrated in FIG. 1.

The organic luminescence display device 1000 of FIG. 1 according to thepresent embodiment may include a substrate 100, a display unit 200, athin-film encapsulation layer 300, and a stress-reducing layer 400.

The substrate 100 may include various materials. For example, thesubstrate 100 may include a glass material or other insulatingmaterials, or a metal thin film.

In one embodiment, the substrate 100 may include at least one selectedfrom a silicone-based polymer, polyurethane, polyurethane acrylate, anacrylate polymer, and an acrylate terpolymer. Examples of thesilicone-based polymer are polydimethylsiloxane (PDMS) andhexamethyldisiloxane (HMDSO).

The display unit 200 is formed on the substrate 100. The display unit200 may generate visible rays that a user may recognize. The displayunit 200 may include various devices, for example, an organiclight-emitting device or a liquid crystal display device.

As illustrated in FIG. 2, in the present embodiment, the display unit200 includes an organic light-emitting device OLED.

The organic light-emitting device OLED may include a first electrode281, an intermediate layer 283 including an organic emission layer, anda second electrode 285.

Each of the first electrode 281 and the second electrode 285 may includevarious conductive materials.

In a selective embodiment, the first electrode 281 and/or the secondelectrode 285 may include a light-transmissible material or alight-reflectible material.

The light-transmissible material may include ITO, IZO, ZnO, or In₂O₃,and the light-reflectible material may include Ag, Mg, Al, Pt, Pd, Au,Ni, Nd, Ir, Cr, or a compound of these.

The intermediate layer 283 is formed between the first electrode 281 andthe second electrode 285, and may include an organic emission layer.

In one embodiment, the intermediate layer 283 may include an organicemission layer, and may further include at least one of a hole injectionlayer (HIL), a hole transport layer, an electron transport layer, and anelectron injection layer. However, the present embodiment is not limitedthereto. In some embodiments, the intermediate layer 283 may include anorganic emission layer and may further include other various functionallayers.

As illustrated in FIG. 1, in the present embodiment, the thin-filmencapsulation layer 300 may be used to completely seal the display unit200, thereby protecting the display unit 200 from external moisture oroxygen.

In one embodiment, the thin-film encapsulation layer 300 may be formedon the display unit 200, and ends of the thin-film encapsulation layer300 may be attached on the substrate 100.

In detail, as illustrated in FIG. 1, after the display unit 200 isformed on the substrate 100, a central portion of the thin-filmencapsulation layer 300 covers the display unit 200, and ends of thethin-film encapsulation layer 300 are attached on the substrate 100.

The stress-reducing layer 400 may be formed on the thin-filmencapsulation layer 300, and may include an organic molecular film.

In one embodiment, the stress-reducing layer 400 may include an organicmolecular film having liquidity.

The stress-reducing layer 400 may protect a top portion of the thin-filmencapsulation layer 300 from cracking in the manufacturing course of theorganic luminescence display device 1000, and ultimately, damage to theorganic light-emitting device OLED, caused by further cracking of thethin-film encapsulation layer 300 and the display unit 200, may beprevented.

In one embodiment, the stress-reducing layer 400 may include aself-assembled monolayer (SAM). The SAM has excellent liquidity.Accordingly, even when stress occurs, the stress-reducing layer 400 mayabsorb the stress by changing its shape.

In another selective embodiment, the stress-reducing layer 400 mayinclude a fatty acid. The fatty acid may also have excellent liquiditydue to its chain molecular structure, and accordingly, once stressoccurs, the fatty acid may absorb the stress.

In one embodiment, the stress-reducing layer 400 may include a stearicacid, which is an example of a saturated fatty acid.

In one embodiment, a thickness of the stress-reducing layer 400 may bein a range of about 1 nm to 3 nm. However, the thickness of thestress-reducing layer 400 is not limited thereto, and may vary as longas the stress-reducing layer 400 does not allow the top portion of thethin-film encapsulation layer 300 to crack and absorbs stress.

Referring to FIG. 2, the display unit 200 includes a thin filmtransistor TFT and the organic light-emitting device OLED. Hereinafter,the display unit 200 will be described in detail.

A buffer layer 110 may be formed on the substrate 100. The buffer layer110 may act as a barrier layer to block diffusion of impurity ions andpermeation of moisture or external gas, and to planarize a surface ofthe substrate 100, and/or a blocking layer.

The thin film transistor TFT may be formed on the buffer layer 110. Thethin film transistor TFT may include an active layer A which may includepolysilicon. The active layer A may include a channel region withoutimpurities doped thereon, and a source region and a drain region, eachwith impurities doped thereon, wherein the source region and the drainregion are respectively located on sides of the channel region. Herein,impurities may vary according to a thin film transistor, and may be anN-type impurity or a P-type impurity.

Once the active layer A is formed, a gate insulating film 210 may beformed on the active layer A, covering the entire surface of thesubstrate 100. The gate insulating film 210 may be a single ormulti-layer, which includes an inorganic material, such as silicon oxideor silicon nitride. The gate insulating film 210 insulates the activelayer A from a gate electrode G located thereabove.

Once the gate insulating film 210 is formed, the gate electrode G may beformed on the gate insulating film 210. The gate electrode G may beformed by photolithography and etching.

A material for forming the gate electrode G may include at least onemetal selected from molybdenum (Mo), aluminum (Al), platinum (Pt),palladium (Pd), silver (Ag), magnesium (Mg), gold (Au), nickel (Ni),neodymium (Nd), iridium (Ir), chromium (Cr), nickel (Li), calcium (Ca),titanium (Ti), tungsten (W), and copper (Cu).

Once the gate electrode G is formed, a first interlayer insulating film230 may be formed thereon, covering the entire surface of the substrate100.

The first interlayer insulating film 230 may include an inorganicmaterial. For example, the first interlayer insulating film 230 mayinclude metal oxide or metal nitride. Examples of the inorganic materialare silicon oxide (SiO₂), silicon nitride, nitride siliconic acid(SiON), aluminum oxide (Al₂O₃), titanium oxide (TiO₂), tantalum oxide(Ta₂O₅), hafnium oxide (HfO₂), and zinc oxide (ZrO₂).

The first interlayer insulating film 230 may be a single- or multi-layerincluding an inorganic material, such as silicon oxide and/or siliconnitride. In some embodiments, the first interlayer insulating film 230may have a two-layer structure of silicon oxide/silicon nitride orsilicon nitride/silicon oxide.

A source electrode S and a drain electrode D, constituting a thin filmtransistor, may be disposed on the first interlayer insulating film 230.

Each of the source electrode S and the drain electrode D may include atleast one metal selected from aluminum (Al), platinum (Pt), palladium(Pd), silver (Ag), magnesium (Mg), gold (Au), nickel (Ni), neodymium(Nd), iridium (Ir), chromium (Cr), nickel (Li), calcium (Ca), molybdenum(Mo), titanium (Ti), tungsten (W), and copper (Cu).

A via-layer 250 may be formed on the entire surface of the substrate100, covering the source electrode S and the drain electrode D. Thefirst electrode 281 may be formed on the via-layer 250. According to theembodiment illustrated in FIG. 1, the first electrode 281 is connectedto the drain electrode D through a via-hole.

The via-layer 250 may include an insulating material. For example, thevia-layer 250 may be a single layer or a multi-layer formed by usingvarious deposition methods using an inorganic material, an organicmaterial, or an organic/inorganic composite. In some embodiments, aplanarization film PL may include at least one material selected from apolyacrylate resin, an epoxy resin, a phenolic resin, a polyamidesresin, a polyimide resin, an unsaturated polyester resin, a polyphenylene resin, a poly phenylenesulfide resin, and a benzocyclobutene(BCB).

The organic light-emitting device OLED may be disposed on the via-layer250. The organic light-emitting device OLED may include the firstelectrode 281, the intermediate layer 283 including an organic emissionlayer, and the second electrode 285. The organic luminescence displaydevice 1000 may further include a pixel-defining layer 270.

At least one of the first electrode 281 and the second electrode 285 mayinclude a transparent electrode or a reflective electrode. When thefirst electrode 281 or the second electrode 285 includes a transparentelectrode, the transparent electrode may include ITO, IZO, ZnO, orIn₂O₃, and when the first electrode 281 or the second electrode 285includes a reflective electrode, the reflective electrode may include areflection film formed by using Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr,or a compound of these, and a transparent film formed by using ITO, IZO,ZnO or In₂O₃. In some embodiments, the first electrode 281 or the secondelectrode 285 may have the structure of ITO/Ag/ITO.

The pixel-defining layer 270 may define a pixel region and a non-pixelregion. The pixel-defining layer 270 has an opening partially exposingthe first electrode 281, and may cover the entire surface of thesubstrate 100. The intermediate layer 283 may be formed inside theopening 270 a, and accordingly, the opening 270 a may substantially actas a pixel region.

FIG. 3 is a cross-sectional view of the organic luminescence displaydevice 1000 according to an exemplary embodiment, including an enlargedview of the thin-film encapsulation layer 300 constituting the organicluminescence display device 1000.

In one embodiment, the thin-film encapsulation layer 300 has a stackstructure of a plurality of thin-film layers, including an inorganicfilm 310 and an organic film 330, which are alternately stacked.

In one embodiment, as illustrated in FIG. 3, the thin-film encapsulationlayer 300 may include a first inorganic film 310 a, a first organic film330 a, a second inorganic film 310 b, and a second organic film 330 b,which are sequentially stacked in this stated order. However, the numberof these films is not limited thereto, and the thin-film encapsulationlayer 300 may be formed by alternately stacking a plurality of layers.

The inorganic film 310 may thoroughly prevent permeation of oxygen ormoisture, and the organic film 330 may absorb stress applied to theinorganic film 310 to provide flexibility.

The inorganic film 310 may be a single film or a stack film includingmetal oxide or metal nitride. In one embodiment, the inorganic film 310may include at least one selected from silicon nitride, Al₂O₃, SiO₂, andTiO₂.

The organic film 330 may include a polymer, for example, a single filmor a stack film formed by using at least one selected from polyethyleneterephthalate, polyimide, polycarbonate, epoxy, polyethylene, andpolyacrylate. For example, the organic film 330 may includepolyacrylate. In detail, the organic film 330 may include apolymerization product of a monomer composition including a diacrylatemonomer and a triacrylate monomer. The monomer composition may furtherinclude a monoacrylate monomer. In some embodiments, the monomercomposition may include a photoinitiator, such as TPO, but embodimentsare not limited thereto.

FIGS. 4A and 4B are respectively schematic views of stress-reducinglayers 400 a and 400 b constituting an organic luminescence displaydevice according to the disclosure. FIG. 4A illustrates an embodiment ofa stress-reducing layer which includes an SAM, and FIG. 4B illustratesan embodiment of a stress-reducing layer which includes a fatty acid.

FIGS. 5A-5D illustrates molecular structures of embodiments of the SAM.FIG. 5E illustrates a molecular structure of a stearic acid, an exampleof the fatty acid.

As illustrated in FIG. 4A, the stress-reducing layer 400 a of an organicluminescence display device according to an exemplary embodiment mayinclude the SAM.

The SAM indicates an organic molecular film that is coated on a surfaceof a substrate, and may include a long-chain alkyl group enablingformation of a regular molecular film and being a body part, a reactivegroup binding to the long-chain alkyl group, and a functional group.

The reactive group forms the head-group of the organic molecular film tobind to a substrate, and the functional group is a tail part of theorganic molecular film and determines the function of a molecular film.

The SAM is coated and aligned on a substrate to form a film, and doesnot require any devices for its formation, and direct chemical bonds arepresent between the surface of the substrate and molecules constitutingthe substrate, thereby providing a strong molecular film even havingfluidity.

In an organic luminescence display device according to the presentembodiment, the reactive group of the SAM may bind to the uppermostlayer of a thin-film encapsulation layer

In some embodiments, the stress-reducing layer 400 a may include any oneof embodiments of the SAM illustrated in FIGS. 5A-5D.

Regarding FIG. 5A illustrates embodiments of the SAM when the reactivegroup is silane, FIG. 5B illustrates embodiments of the SAM when thereactive group is a carboxylic acid, FIG. 5C illustrates embodiments ofthe SAM when the reactive group is a phosphonic acid, and FIG. 5Dillustrates embodiments of the SAM when the reactive group is aprecursor having various structures.

In the case of the embodiments of the SAM of FIG. 5A, the reactivegroups are commonly silane, but functional groups and alkane chainlengths are different from each other.

Therefore, the embodiments of the SAM of FIG. 5A may includeoctyltrichlorosilane (OTS), octadecyltrichlorosilane (OTDS),3-mercaptopropyltrimethoxysilane (MPTMS), hexamethyldisilizane (HMDS),and the like.

Like the embodiments illustrated in FIG. 5A, the embodiments illustratedin FIG. 5B, embodiments illustrated in FIG. 5C, and embodimentsillustrated in FIG. 5D are of the SAM, having different functionalgroups or alkyl chain lengths.

When the stress-reducing layer 400 a of an organic luminescence displaydevice according to the present embodiment includes the SAM,transferring of stress to the thin-film encapsulation layer 300 disposedthereunder and cracking of the thin-film encapsulation layer 300 may beprevented.

This is because the SAM includes a reactive group, an alkyl chain, and afunctional group, and accordingly, even when stress occurs above theSAM, due to the cushioning of a long alkane chain being the body part,the long alkyl chain absorbs the stress, thereby preventing thetransferring of stress toward under the SAM.

The shape change of the stress-reducing layer 400 a including the SAMoccurring in the manufacturing course of an organic luminescence displaydevice will be described in detail when a method of manufacturing theorganic luminescence display device is explained.

In one embodiment, the stress-reducing layer 400 b of the organicluminescence display device may include a fatty acid.

FIG. 4B illustrates a view of the stress-reducing layer 400 b thatincludes a fatty acid according to the present embodiment, and the fattyacid is represented as a circle. However, the fatty acid also has achain shape, and the embodiment of FIG. 4B is presented herein toexplain another embodiment of a stress-reducing layer which is differentfrom the stress-reducing layer 400 a being the SAM, and the shape of thefatty acid is not limited thereto.

A fatty acid refers to a chain-shape saturated or unsaturated monocarboxylic acid. When fat is hydrolyzed, the fat is decomposed intoglycerol and a fatty acid. Fatty acids are classified as a saturatedfatty acid and an unsaturated fatty acid according to a carbon bond.When a fatty acid has a double bond in its chain, the fatty acid isclassified as an unsaturated fatty acid, and when a fatty acid does nothave the double bond in its chain, the fatty acid is classified as asaturated fatty acid.

In one embodiment, the stress-reducing layer 400 b may include a stearicacid illustrated in FIG. 5E.

As illustrated in FIG. 5E, the stearic acid has a structure that has along non-polar hydrocarbon chain having a terminal polar carboxylicgroup attached thereto, and the hydrocarbon chain is 17 carbon atomslong. The stearic acid is an example of the saturated fatty acid.

The stearic acid has a boiling point of 656K (383° C.) and a meltingpoint of 342K to 344.5K (71.5° C.).

Accordingly, in the case in which the stress-reducing layer 400 bincludes a stearic acid and is solid, when the stress-reducing layer 400b is exposed to a temperature close to the melting point of the stearicacid, that is, 71.5° C., the stearic acid begins to change into a liquidstate, thereby providing flexibility.

When the solid stress-reducing layer 400 b is heated at a temperatureequal to or higher than 71.5° C., phase change may occur andaccordingly, the stearic acid may change into a liquid phase.

As a result, in the case of the stress-reducing layer 400 b including astearic acid, even when stress occurs above the stress-reducing layer400 b, due to the flexibility or liquefaction of the stearic acidforming the stress-reducing layer 400 b, transferring stress to theunderlying structure of the stress-reducing layer 400 b and cracking ofthe underlying structure may be prevented.

The phase change of the stress-reducing layer 400 a including a stearicacid occurring in the manufacturing course of an organic luminescencedisplay device will be described in detail when a method ofmanufacturing the organic luminescence display device is explained.

Hereinafter, a method of manufacturing an organic luminescence displaydevice, according to the disclosure, will be described in detail.

FIGS. 6A to 6E illustrate cross-sectional views of an organicluminescence display device 2000 to explain a method of manufacturingthe organic luminescence display device 2000, according to an exemplaryembodiment. Referring to FIGS. 6A to 6E, reference numerals that areidentical to those used in connection with FIGS. 1 to 5 denote likeelements explained in connection with FIGS. 1 to 5, and description ofsuch elements will be omitted herein.

The method of manufacturing the organic luminescence display device2000, according to the present embodiment, includes preparing a carriersubstrate 10, forming the display unit 200 on the carrier substrate 10,forming the thin-film encapsulation layer 300 sealing the display unit200, forming the stress-reducing layer 400 a on the thin-filmencapsulation layer 300, and forming a top protection film 500 on thestress-reducing layer 400 a.

The carrier substrate 10 may act as a base carrier on which the displayunit 200 is initially formed before components including the displayunit 200 and the thin-film encapsulation layer 300 are transferred ontothe substrate 100, which may be a thin glass film or may include aplastic material, such as PET or PI, to improve flexibility of theorganic luminescence display device 2000. The carrier substrate 10 mayinclude a rigid material, such as glass.

In detail, in manufacturing the organic luminescence display device 2000with enhanced flexibility, instead of forming components including thedisplay unit 200 directly on the substrate 100 which may be a thin glassfilm or may include a plastic material, the components may be formed onthe carrier substrate 10 that is formed by using a rigid material, suchas glass, and then, transferred all at once.

The method of manufacturing the organic luminescence display device2000, according to the present embodiment, may further include, prior tothe preparing the carrier substrate 10 and the forming the display unit200 on the carrier substrate 10, forming a sacrificial layer 30.

The sacrificial layer 30 may be formed between the carrier substrate 10and the display unit 200 to protect the display unit 200 from beingdamaged during when the carrier substrate 10 is separated fromcomponents including the display unit 200 and the thin-filmencapsulation layer 300 on the carrier substrate 10.

In one embodiment, the sacrificial layer 30 may include an inorganicmaterial. In one embodiment, the sacrificial layer 30 may have athickness of about 500 Å to about 2000 Å.

In one embodiment, the sacrificial layer 30 may include molybdenumoxide. When the sacrificial layer 30 includes molybdenum oxide, thesacrificial layer 30 may be formed as follows.

First, molybdenum (Mo) metal is deposited on the carrier substrate 10,and then, annealed for about one hour at a temperature of 450° C. Whenheated, molybdenum (Mo) metal may be oxidized and deposited asmolybdenum oxide. A SiO₂ film is formed on the molybdenum oxide througha low-temperature CVD process to form the sacrificial layer 30.

Once the sacrificial layer 30 is formed on the carrier substrate 10, thedisplay unit 200 may be formed thereon.

In detail, in one embodiment, the display unit 200 may be formed on thecarrier substrate 10 either without an intervening layer therebetweenor, as illustrated in FIG. 6A, with the sacrificial layer 30 between thecarrier substrate 10 and the display unit 200.

As described above, the display unit 200 may include the thin filmtransistor TFT and the organic light-emitting device OLED.

After the display unit 200 is formed, the thin-film encapsulation layer300 sealing the display unit 200 may be formed. In the organicluminescence display device 2000 according to the present embodimentillustrated in FIGS. 6A to 6E, the thin-film encapsulation layer 300 islocated on the display unit 200.

The thin-film encapsulation layer 300 is used to completely seal thedisplay unit 200 from external oxygen or moisture, and like in theorganic luminescence display device (see 1000 of FIG. 1), the thin-filmencapsulation layer 300 may cover the display unit 200 in such a mannerthat ends of the thin-film encapsulation layer 300 are attached to thesubstrate 100, thereby enabling a complete sealing of the display unit200.

The stress-reducing layer 400 a may be formed on the thin-filmencapsulation layer 300, and in the case of the organic luminescencedisplay device 2000 according to the present embodiment, thestress-reducing layer 400 a may include the SAM.

The top protection film 500 may be formed on the stress-reducing layer400 a, and the top protection film 500 may be attached on thestress-reducing layer 400 a with an adhesive layer 450.

The top protection film 500 may be the uppermost layer to protect theorganic luminescence display device 2000 from being damaged by externalmoisture or oxygen or external impact in the manufacturing course of theorganic luminescence display device 2000. In detail, the top protectionfilm 500 is a temporal component that is used to protect the organicluminescence display device 2000 in the manufacturing course of theorganic luminescence display device 2000, and the top protection film500 does not remain in a final organic luminescence display device.

In one embodiment, the top protection film 500 may include a plasticmaterial, such as PET, but a material for forming the top protectionfilm 500 is not limited thereto.

Referring to FIG. 6B, once the display unit 200, the thin-filmencapsulation layer 300, the stress-reducing layer 400 a, and the topprotection film 500 are sequentially formed on the carrier substrate 10,the carrier substrate 10 may be removed from the resultant structure.

The carrier substrate 10 may be separated from the display unit 200 byusing a laser lift-off process using a laser, as illustrated in FIG. 6B.

In other words, a laser is irradiated to the sacrificial layer 30 formedon the carrier substrate 10 to separate the carrier substrate 10 and thesacrificial layer 30 from the display unit 200.

In this regard, due to the formation of the sacrificial layer 30, whenthe carrier substrate 10 is separated from the display unit 200, thedisplay unit 200 may be protected from being thermally damaged orcracking.

In the laser lift-off process, due to the irradiation of a laser, heatis generated and transferred to the display unit 200, the thin-filmencapsulation layer 300, the stress-reducing layer 400 a, the adhesivelayer 450, and the top protection film 500, which are disposed above thecarrier substrate 10.

Referring to FIG. 6C, due to the transferred heat, the adhesive layer450 expands, and also, the top protection film 500 including a plasticmaterial attached on the adhesive layer 450 expands.

In this regard, when the adhesive layer 450 and the top protection film500 are formed directly on the thin-film encapsulation layer 300, thethin-film encapsulation layer 300 may receive the stress caused by theexpansion of the adhesive layer 450 and the top protection film 500 andinterface-cracking may occur, thereby affecting the thin-filmencapsulation layer 300 and the display unit 200 and damaging theorganic light-emitting device OLED.

However, in the case of the organic luminescence display device 2000according to the present embodiment, the stress-reducing layer 400 aincluding the SAM is formed between the thin-film encapsulation layer300 and the top protection film 500, and accordingly, thestress-reducing layer 400 a absorbs stress and cracking may beprevented.

When the adhesive layer 450 and the top protection film 500 disposedthereabove expand, the stress-reducing layer 400 a including the SAM maychange in shape due to the liquidity of the long alkyl chain being thebody part. The SAM includes the long alkyl chain being the body part, afunctional group bonded to the alkyl chain, and a reactive group. Due tosuch a structure, the SAM may change in shape while retaining liquidity.

That is, as illustrated in FIG. 6C, a top portion of the stress-reducinglayer 400 a attached on the adhesive layer 450 and the top protectionfilm 500 expands together with the adhesive layer 450 and the topprotection film 500, absorbing stress.

Accordingly, stress-induced cracking and transferring of the cracking tocomponents located at a lower level than where the cracking occurs maybe prevented.

Referring to FIG. 6D, after the carrier substrate 10 and the sacrificiallayer 30 are separated and removed from the display unit 200, theadhesive layer 450 and the top protection film 500 may be cooled andthus shrunken, and due to the shrinking the adhesive layer 450 and thetop protection film 500, the underlying stress-reducing layer 400 a maychange in shape correspondingly, thereby shrinking.

As described above, when the method of manufacturing the organicluminescence display device 2000 according to the present embodiment isused, stress is absorbed by the stress-reducing layer 400 a when thelaser lift-off process is performed, and the carrier substrate 10 may beseparated from the display unit 200 without cracking.

Referring to FIG. 6E, after the removal of the carrier substrate 10, thesubstrate 100 may be attached on the display unit 200 and the topprotection film 500 may be removed. A barrier layer which blocksdiffusion of impurity ions, permeation of external gas, and planarizesthe surface of the substrate 100, and/or a buffer layer (see 110 of FIG.2) acting as a blocking layer may be formed on the substrate 100.

After the display unit 200 is attached on the substrate 100, the topprotection film 500 is removed together with the adhesive layer 450.

FIGS. 7A to 7E illustrate cross-sectional views of an organicluminescence display device 3000 to explain a method of manufacturingthe organic luminescence display device 3000 according to an exemplaryembodiment. Referring to FIGS. 7A to 7E, reference numerals that areidentical to those used in connection with FIGS. 6A to 6E denote likeelements explained in connection with FIGS. 6A to 6E, and description ofsuch elements will be omitted herein.

The method of manufacturing the organic luminescence display device 3000according to the present embodiment includes preparing a carriersubstrate 10, forming the display unit 200 on the carrier substrate 10,forming the thin-film encapsulation layer 300 sealing the display unit200, forming the stress-reducing layer 400 b on the thin-filmencapsulation layer 300, and forming a top protection film 500 on thestress-reducing layer 400 b.

In the organic luminescence display device 3000 according to the presentembodiment illustrated in FIGS. 7A to 7E, the thin-film encapsulationlayer 300 is disposed on the display unit 200. However, as in theembodiment explained in connection with FIG. 6A to FIG. 6E, like theorganic luminescence display device (see 1000 of FIG. 1) of FIG. 1, thethin-film encapsulation layer 300 covers the display unit 200 in such amanner that ends of the thin-film encapsulation layer 300 are attachedon the substrate 100, thereby enabling a complete sealing of the displayunit 200.

As illustrated in FIG. 7A, the stress-reducing layer 400 b may be formedon the thin-film encapsulation layer 300, and in the case of the organicluminescence display device 3000 according to the present embodiment,the stress-reducing layer 400 b may include a fatty acid.

In one embodiment, the stress-reducing layer 400 b may include a stearicacid.

Referring to FIG. 7B, the carrier substrate 10 may be separated from thedisplay unit 200 by using a laser lift-off process using a laser.

In other words, a laser is irradiated to the sacrificial layer 30 formedon the carrier substrate 10 to separate the carrier substrate 10 and thesacrificial layer 30 from the display unit 200.

In the laser lift-off process, due to the irradiation of a laser, heatis generated and transferred to the display unit 200, the thin-filmencapsulation layer 300, the stress-reducing layer 400 b, the adhesivelayer 450, and the top protection film 500, which are disposed above thecarrier substrate 10.

Referring to FIG. 7C, due to the transferred heat, the adhesive layer450 expands, and also, the top protection film 500 including a plasticmaterial attached on the adhesive layer 450 expands.

In this regard, when the adhesive layer 450 and the top protection film500 are formed directly on the thin-film encapsulation layer 300, thethin-film encapsulation layer 300 may receive the stress caused by theexpansion of the adhesive layer 450 and the top protection film 500 andinterface-cracking may occur, thereby affecting the thin-filmencapsulation layer 300 and the display unit 200 and damaging theorganic light-emitting device OLED.

However, in the case of the organic luminescence display device 3000according to the present embodiment, the stress-reducing layer 400 bincluding the stearic acid is formed between the thin-film encapsulationlayer 300 and the top protection film 500, and accordingly, thestress-reducing layer 400 b absorbs stress and cracking may beprevented.

As described above, the stearic acid constituting the stress-reducinglayer 400 b has a boiling point of 656K (38° C.) and a melting point of342 to 344.5K (71.5° C.)

Accordingly, when heat having a temperature equal to or higher than themelting point (71.5° C.) of the stearic acid is transferred to thestress-reducing layer 400 b, the stress-reducing layer 400 b changes inphase from a solid state to a liquid state, and when the stress-reducinglayer 400 b in the liquid state is cooled to a temperature lower thanthe melting point (71.5° C.), the stress-reducing layer 400 b may returnto its solid state.

In other words, referring to FIG. 7C, due to the transferred heat, theadhesive layer 450 and the top protection film 500 may expand, and thestress-reducing layer 400 b including the stearic acid may be liquefiedor may become flexible so that the stress-reducing layer 400 b mayexpand together with the adhesive layer 450 and the top protection film500.

When the carrier substrate 10 is removed by using a laser lift-offprocess and then the temperature is decreased, as illustrated in FIG.7D, the adhesive layer 450 and the top protection film 500 shrink anddue to the decrease in the temperature to the melting point (71.5° C.)or lower, the liquid stearic acid is solidified and the stress-reducinglayer 400 b may shrink.

As described above, when the method of manufacturing the organicluminescence display device 3000 according to the present embodiment isused, stress is absorbed by the stress-reducing layer 400 b when thelaser lift-off process is performed, and the carrier substrate 10 may beseparated from the display unit 200 without cracking.

Referring to FIG. 7E, after the removal of the carrier substrate 10, thesubstrate 100 may be attached on the display unit 200 and the topprotection film 500 may be removed. A barrier layer which blocksdiffusion of impurity ions, permeation of external gas, and planarizesthe surface of the substrate 100, and/or a buffer layer (see 110 of FIG.2) acting as a blocking layer may be formed on the substrate 100.

After the display unit 200 is attached on the substrate 100, the topprotection film 500 is removed together with the adhesive layer 450.

According to the above-described embodiments, cracking occurring when acarrier substrate is separated from a display unit may be prevented.

Other effects of the disclosure may also be inducible in view of thedescription provided above in connection with the drawings.

It should be understood that exemplary embodiments described hereinshould be considered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each exemplaryembodiment should typically be considered as available for other similarfeatures or aspects in other exemplary embodiments.

While one or more exemplary embodiments have been described withreference to the figures, it will be understood by those of ordinaryskill in the art that various changes in form and details may be madetherein without departing from the spirit and scope of the presentdisclosure as defined by the following claims.

What is claimed is:
 1. An organic luminescence display devicecomprising: a substrate; a display unit on the substrate; a thin-filmencapsulation layer sealing the display unit; and a stress-reducinglayer on the thin-film encapsulation layer, wherein the stress-reducinglayer comprises an organic molecular film.
 2. The organic luminescencedisplay device of claim 1, wherein the stress-reducing layer has athickness of about 1 nm to about 3 nm.
 3. The organic luminescencedisplay device of claim 1, wherein the organic molecular film is aself-assembled monolayer.
 4. The organic luminescence display device ofclaim 3, wherein the self-assembled monolayer comprises an alkyl chainbeing a body part thereof, a reactive group linked to the alkyl chainand attached on the thin-film encapsulation layer, and a functionalgroup linked to the alkyl chain, wherein the reactive group is selectedfrom silane, a carboxylic acid, and a phosphonic acid, and thefunctional group is selected from NH₂, OH, COOH, and an alkyl group. 5.The organic luminescence display device of claim 1, wherein thestress-reducing layer comprises a fatty acid.
 6. The organicluminescence display device of claim 5, wherein the fatty acid isstearic acid having a carbon chain.
 7. A method of manufacturing anorganic luminescence display device, the method comprising: preparing acarrier substrate; forming a display unit on the carrier substrate;forming a thin-film encapsulation layer sealing the display unit;forming a stress-reducing layer on the thin-film encapsulation layer;and forming a top protection film on the stress-reducing layer, whereinthe stress-reducing layer comprises an organic molecular film.
 8. Themethod of claim 7, wherein the stress-reducing layer has a thickness ofabout 1 nm to about 3 nm.
 9. The method of claim 7, wherein the organicmolecular film is a self-assembled monolayer.
 10. The method of claim 7,wherein the stress-reducing layer comprises a fatty acid.
 11. The methodof claim 10, wherein the fatty acid comprises a stearic acid having acarbon chain.
 12. The method of claim 7, further comprising after thepreparing the carrier substrate, forming a sacrificial layer on thecarrier substrate.
 13. The method of claim 12, wherein the sacrificiallayer comprises an inorganic material and has a thickness of about 500nm to about 2000 nm.
 14. The method of claim 12, wherein the sacrificiallayer comprises molybdenum oxide.
 15. The method of claim 12, furthercomprising, after the forming the top protection film, removing thecarrier substrate by irradiating a laser to the sacrificial layer toseparate the carrier substrate from the display unit.
 16. The method ofclaim 15, wherein the stress-reducing layer comprises a self-assembledmonolayer, and when the laser is irradiated, the stress-reducing layerexpands, and after the carrier substrate is removed, the stress-reducinglayer shrinks.
 17. The method of claim 15, wherein the stress-reducinglayer comprises a fatty acid, and when the laser is irradiated and afterthe carrier substrate is removed, the stress-reducing layer changes inphase.
 18. The method of claim 17, wherein when the laser is irradiated,the stress-reducing layer is liquefied, and after the carrier substrateis removed, the stress-reducing layer is solidified.
 19. The method ofclaim 12, further comprising: after the carrier substrate is removed,attaching a substrate on the display unit; and removing the topprotection film.